Designers of absorbent articles have traditionally relied upon results from physical testing of prototypes to evaluate the performance of absorbent articles and as a basis for making design changes. Developing prototypes of absorbent articles can be expensive because the equipment necessary to manufacture the absorbent article may not be developed at the time when new absorbent articles are being designed. In some instances, the materials from which the absorbent article will be constructed have yet to be developed. Furthermore, physical testing often requires working in a controlled laboratory environment, which can be expensive. In the case of hygienic products, such as catamenial devices, wound dressings, facial tissue, diapers, and diaper wipes, laboratory personnel may be exposed to increased risks to their health as a result of handling animal exudates during laboratory tests. For absorbent articles designed to absorb other materials, physical testing may require that laboratory personnel be exposed to unhealthy chemicals that the absorbent article is designed to absorb.
Obtaining data describing the transient behavior of absorbent articles can be challenging. Often, a designer of absorbent articles is interested in how the absorbent article being designed acquires exudate at the onset of exposure to an exudate. By the time the designer removes the absorbent article from exposure to the exudate, dissects the absorbent article, places portions of the absorbent article in a device capable of measuring distribution of exudate, and measures the distribution of the exudate, the distribution of the exudate can change significantly as compared to the distribution of exudate when the absorbent article was removed from contact with the exudate.
In some design processes for designing absorbent articles based on physical testing, physical testing on replicates of absorbent articles is needed to deduce conclusions based on observed results from testing. Testing replicates can help reduce uncertainty in making evaluations of different designs for absorbent articles and making decisions on how to improve the design of an article. Creating prototypes that are precise replicates of one another can be challenging. When prototypes are not precise replicates of one another, interpreting testing results can be more difficult.
The fluid transport properties of absorbent materials commonly used in absorbent articles can be difficult to measure. Key fluid transport properties, which partially describe interactions between the absorbent and exudate, include the capillary pressure versus saturation function and the relative permeability function. Most commonly used methods for measuring the absorbent-fluid interaction properties are not suitable for testing with fluids other than water. Further, most methods run an iterative computation wherein the exudate is placed in contact, the substrate is allowed to react, and then the exudate reacts to the substrate. This iteration repeats itself until the model has ended. While this iteration is a good approximation, it does not fully model the real world interaction wherein the exudate and the substrate react simultaneously to each other. Also, unlike the previously modeled exudates, many bodily exudates may take the form of a Non-Newtonian fluid and/or a mixture of fluids and solid components.
There is a continuing unaddressed need for methods for developing absorbent articles that integrates physical measurements of the absorbent properties of absorbent materials into the design process.
Additionally, there is a continuing unaddressed need for virtual product development methods that allow the product developer to gather data on the distribution of Non-Newtonian exudates when placed in contact with the absorbent article while simultaneously changing the properties of the substrate in contact with the Non-Newtonian fluid and/or a mixture of fluids and solid components.
Further, there is a continuing unaddressed need for methods for developing absorbent articles that do not rely entirely on physical testing of prototypes.
There is also a continuing unaddressed need for product designers to be able to test absorbent materials and designs for absorbent articles without having to expose personnel to the substances absorbent articles are designed to absorb.